It is well known that combustion turbine power generating systems have significant power degradation associated with increased ambient temperature or high elevations. This loss of power is primarily associated with the reduced inlet airflow mass of the combustion turbine power generating systems, caused by the reduced inlet ambient air density.
There are a number of technologies that pre-condition inlet air to recover power lost by combustion turbines due to high ambient temperatures/high elevation. For example, evaporative coolers, inlet fogging and “wet compression” technologies provide power augmentation by a combination of inlet air humidification and cooling with associated increased mass flow through the combustion turbine. However, this type of inlet air cooling is limited in areas that don't have a sufficient supply of water available. Inlet chillers also treat ambient air by cooling ambient air with chillers and provide a corresponding increased mass flow and power augmentation. However, high capital cost and high operating and maintenance costs are associated with these chillers.
Thus, there is a need to cool combustion turbine inlet air by mixing it with cold air extracted, for example, from an external air expander exhaust providing an effective alternative power augmentation option: power augmentation of a combustion turbine power generation system with additional power provided by an expander.